Description

Returns wave numbers used in real Fourier transform.

Usage

1

Arguments

n

Number of grid points on each axis. n x n is the total number of spatial points.

Value

Returns a list with

wave

A 2 x n^2 matrix with wavenumbers used in the real Fourier
transform. The first four columns contain the wavenumbers that are only used by cosine terms and not by sine terms. Subsequent columns alternate between wavenumbers of cosine and sine terms.

indCos

Vector of integers indicating the position of columns in
'wave' of wavenumbers of cosine terms. The first four cosine wavenumbers in 'wave' are not included in 'indCos'.